docstr: Define an alias, but don't raise on an AliasError.
docstr_tok: ["Define","an","alias",",","but","do","n't","raise","on","an","AliasError","."]
code: def soft_define_alias(self, name, cmd):
      """Define an alias, but don't raise on an AliasError."""
      try:
          self.define_alias(name, cmd)
      except AliasError as e:
          error("Invalid alias: %s" % e)
  
imports: import os
  import re
  import sys
  from traitlets.config.configurable import Configurable
  from .error import UsageError
  from traitlets import List, Instance
  from logging import error
label_desc: Use image node_id 4 for calling the AliasManager obj's underlying member method code with example usage: obj.soft_define_alias(name, cmd) without return types